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| May-11-08 | | patzer2: While I got a few of the initial moves, I must admit the follow-up with several key moves not involving a mate or capture made the combination extremely difficult for me. Since I didn't see <Random Visitor>'s Rybka lines after 17...Kg7 18.Rxh7+ Kg8 19.Qg1! or the mate-in-four for White after the final possibility 21...Kxf5 22. Qh3+ Kf4 23. Qf3+ Kg5 24. Qg4+ Kf6 25. Ne4#, I won't claim to have solved this one. |
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| May-11-08 | | znprdx: Plan#1
16.Rx[B]h6 Kx[R]h6 17.Rh1+ Kx[N]g5 just seems rather fuzzy Plan #2
16.Rh5 (...g6x[R]h5? 17.Ne6+) so that's the easy part Nc7:what else? Black is almost in zugswang
17.Qe1 Bx[N]g5 18.Qg3 seems too slow
Plan #3
16. Nxh7 (Kx[N]h7? 17. Qe1 on the way to h4
Bxe3+ 18. Kb1 Bx[R]g1 19. Nx[R]f8 Kx[N]f8 20. Qx[B]g1 Nc7 21. Bg4 seems like solid chess -hardly insane... OTB I'd probably have wasted valuable time trying to make 16.Bh5 work I've timed out: so I give up
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| May-11-08 | | DarthStapler: I got the first two moves |
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| May-11-08 | | Marmot PFL: The line in the game is pure calculation, but not extremely hard as the king has no escape once the R gets to h7. For instance Rh8 Qg1+ Kf6 Qf2+ Bf5 Qh4+ Ke6 d5+ and mates. More stubborn for black is 17...Kg7 18.Rxh7+ Kg8 where white may not have a forced win black looks terrible. An alternative win the comp spotted was 19.Qg1+ Kf6 20.e5+ de5 21.Ne4+ with rapid mate, which shows how hopeless those exposed king positions are unless the attacker blunders. |
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| May-11-08 | | lost in space: After 16. Rxh6 Kxh6 17. Rh1 Kxg5 18. Qg1+ Kf6 19 Rxh7 Rf7 we have the following poition:
click for larger viewI found no good continuation for White in this position, for example Qf2+ Bf5!! and Black is even slightly better. Any thought?
Therfore I was looking for better moves for white and came up with
17. dxe5.
Any thoughts on this? |
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| May-11-08 | | lost in space: A few more thoughts on the (out of my view) critical poition (see the diagram above). After 20. Qf2+ Bf5 21. Qh4+ g5 there are 4 possible continuations: A: 22. Qh6+ Bg6 23. Bh5 Qg8 is hopeless for White
B: 22. Rh6+ Bg6 23. Qf2 Kg7 24. Rxg6 Kxg6 25. Bh5+ Kxh5 26. Qxf7 Kh6 27. Qxb7 Qc8 and White has nothing but a few pieces less C: 22. Rxf7+ Kxf7 23. Qf2 Qe7 24. Qxf5 Ke8 25. Bh5+ Kd8. Better for Black D: 22. dxe5+ dxe5 23. Rxf7+ Kxf7 24. Qf2 Nc5 25. Qxf5 Qf6 26. b4 Ne6 27. Qh7+ Ng7 18. Bh5+ Ke7 and Blacks position is beatyfull |
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| May-11-08 | | lost in space: The best what White can do is saving the game. After 16. Rxh6 Kxh6 17. dxe5 Kg7 (17...dxe5 18. Nf7+ Rxf7 Qxd8) 18. exd6 Qf6 19. Qd4 Qxd4 20. exd4 Bd7 we have the following position:
click for larger viewThis is looking o.k. for White, but it is far away from a win |
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| May-11-08 | | lost in space: Tried to win the above position (see my last kibitz). By far not foreced, but I tried to find the best moves:
21. e5 Rae8 22. Kd2 c5! 23. Nd5 cxd4 24. Nf6 Rxf6 25. exf6+ Kxf6 26. Nxh7+ Ke5 27. Rxg6 Nc5 28. Nf6 Bf5 29. Rh6 Rd8 30. Bg4 Rxd6 31. Bf5 Rxf6 32. Rxf6 Kfx6 33. Bd3 Ke5 =
click for larger view |
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| May-11-08 | | Marmot PFL: <After 16. Rxh6 Kxh6 17. Rh1 Kxg5 18. Qg1+ Kf6 19 Rxh7 Rf7 we have the following poition: click for larger view
I found no good continuation for White in this position, for example Qf2+ Bf5!! and Black is even slightly better. Any thought? >
You reversed white's 18th and 19th moves, that's what makes Rf7 playable. |
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May-11-08
 | | johnlspouge: Sunday (Insane): White to play and win.
Material: N for B+P. White leads in development, with Rg1 and Rh1 on open files, Rg1 opposing Kg7 and Rh1 threatening Bh6, which significantly is protected only by Kg7. Thus, Rxh6 lures Kg7 onto the 6-th rank. As in previous Sunday puzzles, if a K is isolated and forced to walk a tightrope above his 2-nd rank, a human cannot usually calculate lines to completion, but even 2-piece sacrifices return dividends. The White Qd1 and Be2 form a battery able to infiltrate light squares around Kg7, if an opportunity appears. The White Ng5 controls many light squares near Kg7, so only Nc3 cannot immediately join an attack. Effectively, only 3 pieces (Qd8, Rf8, and Bh6) defend the Black Kg7, so White has a large local superiority and can sustain an attack on the Black Kg7, even if 2 pieces must be sacrificed to initiate it. Candidates (16.): Rxh6
16.Rxh6 Kxh6 [else, drop a B] 17.Rh1+
Black can accept the sacrifice of Ng5.
17…Kxg5
Candidates (18.): Qg1+, Qe1, Rxh7
18.Rxh7
threatening 19.Qe1 20.Qh5+ or 19.Qg1+ 20.Qf2+ and mate soon. Black has several options, but must eventually interpose at f5, lose most of the material, and remain on the tightrope. By my calculation, Black seems to have adequate defenses against the other candidates 18.Qg1+ or 18.Qe1. White needs to make Black commit, before deploying the Qd1 to maximum effect. Black can decline the sacrifice of Ng5.
17…Kg7 18.Rxh7+ Kg8
[18…Kf6 19.Qg1 then 20.Qf2
leads to variations accepting the sacrifice]
19.Qg1 (threatening 20.Qg3 21.Qh4)
seems worth the investment of R for B+P, although there are many complications still. Again, there is a tempting continuation that seems to fail: [19.Qh1 Qxg5 20.Rh8+ Kf7 seems alright for Black]
Acceptance of the second sacrifice, as in the game, seems worse than its refusal. |
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May-11-08
 | | Open Defence: I guessed Rxh6 but could not find the complete variation missed this one |
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| May-11-08 | | lost in space: <Marmot PFL: You reversed white's 18th and 19th moves, that's what makes Rf7 playable.> Muchos gracias! This make really the difference! Now I see the way for White to win. |
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| May-11-08 | | DavidD: The "insane" part of the puzzle arises from the complexity of variations after the first two rather obvious moves 16.Rxh6 Kxh6 and 17.Rh1+. Most players could find the initial moves--they are forcing. The really beautiful move is 18.Rxh7! Weaker players would likely continue to check (e.g., 18.Qg1+) letting the King escape--masters know the value of building a mating net with moves like Rxh7. Because of the myriad of possibilities, it is simply impossible to calculate them all precisely to mate. Thus the combination is intuitive. White certainly saw the position after Rxh7. How much to calculate beyond that is a matter of personal taste and style. Some players would simply judge the position as very good for White since Black's king is exposed and White has Q+R+B to attack, while Black has basically a king devoid of defenders. Other players would happily spend an hour calculating as much as was possible. Either is acceptable for master chess. It takes real chess character and maturity to play such sacrifices in OTB tournament games. We should all be this brave! |
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| May-11-08 | | solskytz: Referring to DavidD, I'm not convinced that it would be completely 'patzer-like' to play 18. Qg1+ before going 19. Rxh7 - actually this was my idea of solving it - getting the queen into the battle one move earlier, transposing moves with Rxh7, and to g1 rather than h1... looks like a minor difference to me. Anyone objecting? (Of course I didn't check with a computer) |
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| May-11-08 | | lost in space: <solskytz>: DavidD is right: 18. Qg1 is not winning; see my posts prior to this one.
Although I don't like the style of <DavidD> post ("weaker players" is rather harsh; he hasn't even shown that he was able to solve this insane puzzle) but from an objective point of view he is right. 18. Qg1+ Kf6 19. Rxh7 Rf7 is better for black. |
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| May-11-08 | | wals: Static Evaluation: White is down a pawn. Has a knight for a bishop. Dynamic Evaluation: The black king is on the seventh.
The f file is open. White has castled long. Bishop h6 is pointed straight at
the King. What happens if Ra1 takes h6. If the King takes, Rh1+ The King is then obliged to take g5, what happens after that is beyond me,
at this time of the morning.
PM = Goodness gracious me, the candidate move was spot on Giuseppe Laco - Mario Lanzani, Imperia Italy 1992
Analysis by Fritz 11: depth 19/46 time 4min 23
1.  (1.63): 16.Rxh6 Kxh6 17.dxe5 Kg7 18.exd6 Qf6 19.Nf3 Be6 20.e5 Qf5 21.Rg5 Qf7 22.Qd4 c5 23.Qh4 Kh8 24.Rg3 Nb4 2.  (-0.81): 16.Rh5 Qe7 17.Kb1 Nc7 18.dxe5 dxe5 19.Nf3 Bxe3 20.Rg2 Ne6 21.Qh1 Kg8 22.Nxe5 Bg5 23.Nxg6 hxg6 24.Rh8+ Kf7 25.Rh7+ (, 12.05.2008)
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May-11-08
| | johnlspouge: <<lost in space> wrote: <solskytz>: DavidD is right: 18. Qg1 is not winning> Yes. In fact, exhibiting poor chess intuition, I calculated lines losing for White from <both> 18.Qg1+ and 18.Qe1 in a couple of hours, which is why I settled on 18.Rxh7, with the analysis I gave. I am therefore understandably skeptical that GMs rely on intuition in complicated positions like this one. After all, someone with intuition would only have to calculate the winning line, which is much easier ;>) |
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May-11-08
| | johnlspouge: <<lost in space> wrote: After 16. Rxh6 Kxh6 17. Rh1 Kxg5 18. Qg1+ Kf6 19 Rxh7 Rf7 we have the following poition [snip]> I achieved this position in my analysis of candidates for move 18.Qg1+, and I could not find a way to win it. I will report back after computer analysis. |
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May-11-08
| | johnlspouge: <<Marmot PFL> wrote: The line in the game is pure calculation, but not extremely hard as the king has no escape once the R gets to h7.> Hi, <Marmot PFL>. We are in agreement, you apparently having arrived there much more efficiently. |
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| May-11-08 | | DavidD: Chess is a fascinating game because of the complexity of thought processes involved in arriving at solutions to very complex problems arising at the board. Very strong players often "solve" a position by different methods of thought. This is why it is so difficult to learn chess thinking--there isn't just one approach. And two approaches (such as the intiuitive nature of sacrificing versus comprehensive calculation of lines) may be just a matter of personal taste. However, you can demonstrate a distinct difference in the thinking of strong players verses weaker players. The dividing line between strong and weak is certainly difficult to define as well. One easily identified trait of weaker players is to check the king constantly. Stronger players have learned to build mating nets around the king with quiet moves. Thus my admiration for 18.Rxh7! rather than continuing with checks with 18.Qg1+. Examining 18.Qg1+ as a candidate move is logical and good; it is the TENDENCY to examine only checks (and to miss moves like 18.Rxh7) that demonstrate an inefficient thinking process. |
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May-11-08
| | johnlspouge: Mom-and-Pop Toga II 1.3.1 valuations follow, under my usual rules. The lines are as the computer gives, so their ends become undependable. The <emphasis> falls on the last move I entered and values are for White. The game line, with acceptance of the double sacrifice, is [ply 15/68, time 09:45, value +5.47]
15…e5 16.Rxh6 Kxh6 17.Rh1+ <Kxg5> 18.Rxh7 Qc7 19.Qg1+ Kf6 20.dxe5+ dxe5 21.Qf2+ Bf5 22.Rxc7 Nxc7 23.exf5 gxf5 24.e4 Ke7 25.exf5 Rf7 26.Ne4 Kd8 27.Qc5 Ne8 28.Qxe5 Re7 29.Qf4 Nf6 30.Qd6+ Nd7 With the move 18...Qc7, the computer is saying that a human would find a way to do worse ;>) Black would have done much better to refuse the second sacrifice and follow the computer's best line for the puzzle position. [ply 15/60+, time 03:44, value +1.59]
15…<e5> 16.Rxh6 Kxh6 17.Rh1+ Kg7 18.Rxh7+ Kg8 19.Qg1 exd4 20.Rh6 Qf6 21.Nh7 Qe5 22.Qxg6+ Qg7 23.Nxf8 dxc3 24.Qxd6 cxb2+ 25.Kb1 Qc3 26.Rg6+ Kf7 27.Rg1 Qh8 The move 18.<Qg1+> gives White an inferior, but probably not a lost position. [ply 15/53, time 03:58, value -0.54]
15…e5 16.Rxh6 Kxh6 17.Rh1+ Kxg5 18.<Qg1+> Kf6 19.Rxh7 Rf7 20.Qf2+ Bf5 21.Rxf7+ Kxf7 22.exf5 Qe7 23.fxg6+ Kg7 24.dxe5 dxe5 25.Ne4 Qe6 26.Ng3 Qxg6 27.Nf5+ Kf8 28.Nh4+ Qf7 29.Qg3 Qg7 30.Ng6+ Kg8 I realize 18.<Qe1> is a personal favorite, but here it is anyway. When followed by a third sac 19.Bxh5 (which I found), White wins if Black accepts. [ply 15/64, time 08:25, value +4.59]
15…e5 16.Rxh6 Kxh6 17.Rh1+ Kxg5 18.Qe1 h5 19.Bxh5 <gxh5> 20.Qh4+ Kg6 21.Qxh5+ Kf6 22.Qh7 Rg8 23.Rf1+ Kg5 24.Rg1+ Kf6 25.Rxg8 Qxg8 26.Qxg8 Ke7 27.Qg7+ Ke8 28.dxe5 dxe5 29.Qxe5+ Kf7 30.Qh5+ Kg7 31.Qe8 Kh6 32.e5 Nc7 33.Qf8+ Kg6 34.Qf6+ Kh5 White goes down miserably if Black refuses the third sac, however. [ply 13/46, time 00:42, value -3.45]
15…e5 16.Rxh6 Kxh6 17.Rh1+ Kxg5 18.<Qe1> h5 19.Bxh5 Kh6 20.Be2+ Kg7 21.Qg3 Be6 22.dxe5 dxe5 23.Qxe5+ Qf6 24.Qg3 Rad8 25.Kb1 Nc5 26.Rf1 Qe7 27.Rh1 Rd2 28.Qe5+ Rf6 Today's puzzle yields an appropriate sermon (with apologies to Gordon Gekko): in chess, greed is not good :) |
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May-11-08
| | johnlspouge: I decided to post again, because I was so surprised by the play from the position
click for larger viewoccurring after refusing the second sacrifice, of the Ng5: 15…e5 16.Rxh6 Kxh6 17.Rh1+ Kg7 18.Rxh7+ Kg8 19.Qg1 <Qf3> I entered 19...<Qf3> as a direct (human-style) answer to the White threats on Pg6. Toga II 1.3.1 gives [ply 15/60, time 06:19, value +4.44]
20.c5 Be6 21.Rxb7 Nxc5 22.dxc5 Rf7 23.Nxf7 Bxf7 24.cxd6 Qxd6 25.Qf1 Rf8 26.Bc4 Bxc4 27.Qxc4+ Kh8 28.Qe2 Kg8 29.Rxa7 Qc5 30.Rd7 Rb8 31.a4 Rb4 The play focuses on achieving the move 26.Bc4 by opening the center, to me a logical continuation of the attack, but coming from very unexpected quarter. |
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| May-11-08 | | sleepyirv: Wasted too much time on trying to make the family fork work on E6. Did finally figure out the first move out though. Black play rather poorly in the game, his king has little defense by 16 and was far behind in development. |
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May-12-08
 | | kevin86: In exchange of R+N vs B,white opens up the black king. T%he rook and queen seal him in,and the other pieces garnish the fine dish:of King-a-la King. |
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| May-13-08 | | Marmot PFL: <johnlspouge:> Hi, <Marmot PFL>. We are in agreement, you apparently having arrived there much more efficiently. More luck than efficiency I'm afraid. Usually I get the main idea but overlook improvements for one side or the other. Those are the ones I don't comment on much. |
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Later Kibitzing> |
Kibitzing
sac: 16.Rxh6